# Signal Server Tag

> **Status:** Active
> **Last updated:** 2026-07-05

Users registered on a signal server can show that server's display tag on their profile card (opened by clicking their name or avatar).

## Responsibilities

- Server: expose a human-readable tag per **endpoint** (not per user identity).
- Client: resolve tag for a user's **home** signaling server (`homeSignalServerUrl`) and render on profile cards.

## Server configuration

`server/data/variables.json` accepts an optional `serverTag` string. When omitted, the server falls back to its public URL built from `serverProtocol`, `serverHost`, and `serverPort` (`server/src/config/variables.ts`).

## Health API

`GET /api/health` includes `serverTag` so clients can cache the display label per configured endpoint.

## WebSocket presence

The client sends `homeSignalServerUrl` in `identify` messages. The signaling server echoes that value in `server_users` and `user_joined` payloads so other clients can resolve the correct tag. See [signaling.md](signaling.md).

## Client behavior

- Login and registration store `homeSignalServerUrl` on the current user.
- Profile cards show the resolved tag beside the username in muted text (`profile-signal-server-tag.component`).
- Configured labels render as `#tag`; URL fallbacks render as a globe icon with the URL in a tooltip.
- Tag resolution (`signal-server-tag.rules.ts`): match `homeSignalServerUrl` against configured endpoints and prefer cached health `serverTag`; otherwise show the raw URL fallback.

## Testing

- `toju-app/src/app/domains/server-directory/domain/logic/signal-server-tag.rules.spec.ts`
- `server/src/websocket/handler-status.spec.ts` (presence payload includes `homeSignalServerUrl`)

## Related

- [server-directory.md](server-directory.md) — endpoint health cache
- [authentication.md](authentication.md) — `homeSignalServerUrl` on identify

## Changelog

| Date | Change |
|------|--------|
| 2026-07-05 | Clarified per-endpoint tag vs per-user home URL; added test references |